Adjustable tripod assembly

ABSTRACT

A leg assembly ( 12 ) for a tripod ( 10 ) comprises a first leg unit ( 13 ), a second leg unit ( 14 ) and a third leg unit ( 15 ). First leg unit ( 13 ) includes legs ( 13 A and  13 B). Second leg unit ( 14 ) includes legs ( 14 A and  14 B). Legs ( 14 A and  14 B) are laterally spaced from each other and held in fixed position by an upper cross member ( 17 ) and a lower cross member ( 18 ). Legs ( 13 A and  13 B) can slide through openings in upper cross member (17). Leg (15A) can slide through an opening in lower cross member ( 18 ). Upper cross member ( 17 ) includes a first fixing means for selectively locking and unlocking the first leg unit in position. The lower cross member ( 18 ) includes a second fixing means for selectively locking and unlocking the third leg unit in position. A first lever ( 23 ) is used to selectively actuate the first fixing means. A second lever ( 24 ) is position adjacent to first lever ( 23 ). Second lever ( 24 ) is connected via a connecting means such as torsion bar ( 25 ) to the second fixing means. First lever ( 23 ) and second lever ( 24 ) can be actuated independently to enable either of the first or second fixing means to be actuated. Alternatively, due to the close proximity of first lever ( 23 ) and second lever ( 24 ), both levers can be actuated simultaneously to effect actuation of the first fixing means and the second fixing means.

FIELD OF THE INVENTION

[0001] The present invention relates to a support means of adjustableheight. The present invention is particularly suitable for use as atripod, such as a tripod used in still photography or moving picturerecording or transmitting. The present invention also relates to a legassembly for use in support means.

BACKGROUND OF THE INVENTION

[0002] Support means of adjustable height, such as tripods, are known inthe present art. One such support means is known as a two stage tripod.Such tripods have three leg assemblies, with each leg assemblycomprising a first leg unit, a second leg unit and a third leg unit. Inorder to enable the height of the tripod to be adjusted, the first andsecond leg units are slidably movable relative to each other and thesecond and third leg units are also slidably movable relative to eachother. Each leg assembly also includes a first fixing means forselectively locking and unlocking the first leg unit relative to thesecond leg unit and a second fixing means for selectively locking andunlocking the second leg unit relative to the third leg unit. When thefirst fixing means is in the unlocked position, the first and second legunits are movable with respect to each other, whilst in the lockedposition the first and second leg units are held in fixed (or locked) inrelation to each other. The second fixing means operates in a similarfashion with respect to the second and third leg units. Such tripods areknown as two stage tripods because they have two fixing means on eachleg assembly.

[0003] Such tripods have found wide acceptance and are used throughoutthe world. Although they are popular, such tripods suffer from thedisadvantage of requiring two fixing means on each leg assembly to beoperated to properly adjust the height thereof. This can be timeconsuming. Moreover, the lower fixing means frequently require that theuser bend over in order to operate them. This can be inconvenient andcause difficulty if the tripod has heavy camera gear mounted thereon.

[0004] One possible solution to the above difficulties has been proposedby Australian Patent No 709257 in the name of Sachtler Agreement(equivalent to U.S. Pat. No. 5,887,835). In this patent, the actuatingmeans for actuating the first fixing means is also connected to thesecond fixing means such that operating the first actuating means tolock the first fixing means also simultaneously locks the second fixingmeans. Similarly, operating the first actuating means to unlock thefirst fixing means also simultaneously unlocks the second fixing means.Thus, locking and unlocking of each leg assembly of the tripod issimplified.

SUMMARY OF THE INVENTION

[0005] In one aspect, the present invention provides a support means ofadjustable height comprising at least one leg assembly having a firstleg unit, a second leg unit and a third leg unit, said first and secondleg units being slidably movable relative to each other, said second andthird leg units being slidably movable relative to each other, firstfixing means for selectively locking and unlocking the first leg unitrelative to the second leg unit, second fixing means for selectivelylocking and unlocking the third leg unit relative to the second legunit, first actuating means for selectively actuating the first fixingmeans between locked and unlocked positions and second actuating meansfor selectively actuating the second fixing means between locked andunlocked positions, characterised in that the first and second actuatingmeans are independently actuatable to selectively and independently lockor unlock the first fixing means and the second fixing means and thefirst actuating means and the second actuating means are positioned inclose proximity to each other such that the first actuating means andthe second actuating means can be operated essentially simultaneously bya user to thereby essentially simultaneously lock or unlock the firstfixing means and the second fixing means.

[0006] It is preferred that the first actuating means and the secondactuating means are operable by the hand of the user.

[0007] The first actuating means and the second actuating means arepreferably positioned substantially adjacent to each other. Preferably,the second actuating means is positioned adjacent to and below the firstactuating means.

[0008] In one embodiment, the second actuating means is positioned awayfrom the second fixing means. In this embodiments, the second actuatingmeans may be connected to the second fixing means by a connectingmember. Operation of the second actuating means will cause theconnecting member to also actuate and move the second fixing means fromthe locked position to the unlocked position and vice versa. Theconnecting means suitably comprises a torsion bar.

[0009] The support means of the present invention is preferably atripod, especially a tripod used for supporting camera equipment. Suchtripods are known and include a platform to which the camera equipment(such as cameras and fluid heads) may be mounted, and three legassemblies attached to the platform. Such tripods may have a number offixing means used to lock the leg assemblies into place when the tripodis correctly adjusted. The present invention encompasses all such fixingmeans.

[0010] An especially suitable fixing means comprises a clamping meansfor clamping the leg units to prevent relative movement of the legunits.

[0011] In one embodiment of the present invention, the first actuatingmeans comprises a first lever and the second actuating means comprises asecond lever. The first and second levers may operate by rotating aroundrespective pivot points. The first and second levers may also include aneccentric such that the levers can be moved to overcome a dead centre tothereby lock the respective fixing means. Again, such arrangements areknown and need not be described further.

[0012] The support means of the present invention is preferably arrangedsuch that the first fixing means and the second fixing means are mountedat a fixed spacing, more preferably with both fixing means mounted tothe second leg unit. This will ensure that the distance between thefirst and second fixing means does not vary. The second leg unit ispreferably an intermediate leg unit, with the first leg unit being anupper leg unit and the third leg unit being a lower leg unit.

[0013] The second leg unit may comprise a plurality of legs spacedlaterally apart, with a first cross member extending between the legs tohold the legs in spaced apart relationship. The first cross-members mayinclude receiving means for slidably receiving one or more legs of thefirst leg unit. The first fixing means may operate by clamping the oneor more legs of the first leg unit. In this fashion, the height of thefirst leg unit relative to the second leg unit can be adjusted.

[0014] Alternatively, the leg(s) of the first leg unit may betelescopically slidable in the legs of the second leg unit.

[0015] The second leg unit may also have a second cross member extendingbetween the plurality of legs of the second leg unit. The second crossmember also assists in holding the legs of the second leg unit in spacedapart relationship. The second cross member may include receiving meansfor slidably receiving one or more legs of the third leg unit. Thesecond fixing means preferably works by clamping the leg(s) of the thirdleg unit.

[0016] Alternatively, the leg(s) of the third leg unit may betelescopically received within the legs of the second leg unit.

[0017] In the embodiment of the present invention which includes firstand second cross members, the first fixing means is preferably mountedon the first cross member and the second fixing means is preferablymounted on the second cross member.

[0018] The present invention provides a support means of adjustableheight in which the height can be easily adjusted and the leg unitslocked into position relative to each other by a simplified action. Theapparatus also provides the added flexibility of being able toindependently lock the leg units such that locking the first and secondleg units relative to each other does not necessarily lock the secondand third leg units relative to each other. In this regard, theapparatus of the present invention can be used in a distinct fashion tothe apparatus disclosed in Australian patent no. 709257.

[0019] The present invention also encompasses the leg assembly describedabove.

[0020] A preferred embodiment of the present invention will now bedescribed with reference to the accompanying drawings in which:

[0021]FIG. 1 shows a three-dimensional view of a camera tripod inaccordance with the present invention;

[0022]FIG. 2 shows a three-dimensional view of the top cross member ofthe tripod of FIG. 1 with the first and second actuating means in theunlocked position;

[0023]FIG. 3 shows a view generally similar to FIG. 2 but with the topactuating means in the locked position.

[0024]FIG. 4 is a similar view to FIG. 1, but with the leg unitsextended;

[0025]FIG. 5 is a cross-sectional view of a first fixing means suitablefor use in the present invention;

[0026]FIG. 6 is a cross-sectional view of a second fixing means suitablefor use in the present invention; and

[0027]FIGS. 7 and 8 are side views of the apparatus of FIG. 1.

[0028] In considering the description hereunder and the accompanyingdrawings, it will be appreciated that the drawings show a presentlypreferred embodiment of the invention and the drawings should not beconsidered to restrict the invention to the specific embodiment showntherein.

[0029] Turning firstly to FIG. 1, it will be noted that FIG. 1 shows oneleg assembly of a tripod. The tripod will, of course, include three legassemblies that are essentially identical to the leg assembly shown inFIG. 1. However, for the sake of clarity, the other two leg assemblieshave been omitted from FIG. 1. The tripod 10, part of which is shown inFIG. 1, includes a platform 11. Platform 11 is designed to have cameraequipment, such as fluid heads and cameras mounted thereto. The tripodfurther includes a first leg assembly 12 and second and third legassemblies (not shown), each leg assembly being mounted to the platform11. The leg assembly 12 is a three-leg unit leg assembly that includesfirst leg unit 13, second leg unit 14 and third leg unit 15. The firstleg unit 13 includes legs 13A and 13B. Similarly, second leg unit 14includes legs 14A and 14B. It can be seen from FIG. 1 that legs 14A and14B of second leg unit 14 are laterally spaced from each other. Thisthird leg unit 15 includes one leg 15A as best shown in FIG. 4.

[0030] It will also be noted that third leg unit 15 includes a foot 16mounted at the lowermost part thereof.

[0031] The leg assembly 12 further includes an upper cross member 17 anda lower cross member 18. Upper cross member 17 includes openings 19, 20(best shown in FIGS. 2 and 3) for slidably receiving legs 13A and 13Btherein. Upper cross member 17 also includes openings 21, 22 forreceiving legs 14A, 14B of the second leg unit 14. It will beappreciated that the top part of legs 14A, 14B are fixedly received inopenings 21 and 22. Openings 21 and 22 act to hold legs 14A, 14B isspaced apart relationship.

[0032] The lower ends of legs 14A, 14B are also received in similaropenings formed in lower cross member 18. This acts to hold the lowerends of legs 14A, 14B in spaced apart relationship.

[0033] It will be appreciated from the above described construction thatthe upper and lower cross members 17, 18 are spaced apart by a fixedamount, this being the length of the legs 14A, 14B.

[0034] Although not clearly shown in the accompanying drawings, thelower cross member 18 also includes an aperture in the lower parttherein to allow the leg 15A of the third leg unit to pass therethrough,such that the leg 15A of the third leg unit 15 can be slidably movedrelative to the legs 14A, 14B of the second leg unit.

[0035] The upper cross member 17 also includes a first fixing meansmounted therein for selectively locking and unlocking the first leg unitin position relative to the second leg unit. Similarly, the lower crossmember IS includes a second fixing means for selectively locking andunlocking the third leg unit in position relative to the second legunit. As the first fixing means and second fixing means are mountedwithin respective upper and lower cross members 17, 18, they are notvisible and therefore are not shown in FIGS. 1 to 3. It will beappreciated that the fixing means may be of any construction known to besuitable to those skilled in the art.

[0036] The leg assembly 12 shown in FIGS. 1 to 3 also includes a firstactuating means 23 which takes the form of a lever pivotally mounted toupper cross member 17. The lever 23 can be moved from an open position,as shown in FIGS. 1 and 2, to a closed position, as shown in FIG. 3. Inthe open position shown in FIGS. 1 and 2, the first fixing means is inthe unlocked position and the first leg unit can slide freely relativeto the second leg unit. In the closed position shown in FIG. 3, thefirst actuating means locks the first fixing means such that the firstleg unit 13 is locked against movement relative to the second leg unit14, thereby locking the first leg unit into position relative to thesecond leg unit.

[0037] The apparatus further includes a second actuating means 24 thatis connected via torsion bar 25 to the second fixing means mountedwithin lower cross member 18. As can be best seen from FIGS. 1 and 2,second actuating means 24 is in the form of a lever that is positionedsubstantially adjacent to and below first actuating means or lever 23.The positioning of the second actuating means 24 in close proximity tofirst actuating means 23 allows the hand of a user to engage both firstand second actuating means 23, 24 simultaneously to thereby enableessentially simultaneous actuation of first and second actuating means23, 24 to thereby selectively lock or unlock both the first fixing meansand the second fixing means. It will be appreciated that actuation ofsecond actuating means 24 causes rotation of torsion bar 25 which thenacts on the second fixing means to move the second fixing means betweenthe locked and unlocked positions. Second actuating means 24 is mountedindependently to first actuating means 23 in the embodiment shown in theFigures

[0038] It will be appreciated that first actuating means 23 and secondactuating means 24 are not connected to each other. This enables firstactuating means 23 to be actuated separately and independently to secondactuating means 24 (and vice versa). Therefore, it is possible tooperate the first fixing means without operating the second fixing means(and vice versa). For example, as shown in FIG. 3, the first actuatingmeans 23 has been moved to the locked position, thereby locking firstfixing means such that the first leg unit is fixed relative to thesecond leg unit, whilst the second actuating means 24 has not beenoperated such that the second fixing means is still in the unlockedstate, thereby allowing relative movement between the second leg unitand the third leg unit. This enables further adjustment of the third legunit to take place.

[0039] It will also be appreciated that the positioning of the secondactuating means 24 in the embodiments shown in the drawings is wellabove the position of the second fixing means. In normal use of theapparatus of the invention, this places the second actuating means 24 ata much more convenient height for the user. It will be appreciated that,in most prior art tripods, the second actuating means was located on thelower cross member 18. This required the user to bend over to operatethe second actuating means. It will also be appreciated that the presentinvention also encompasses other positioning of the first and secondactuating means. For example, the first and second actuating means maybe located near the second locking means, or both may be positionedintermediate the first and second locking means or above the first andsecond locking means. However, the positioning as shown in FIGS. 1 to 4and 7 and 8 is most preferred.

[0040] Specific embodiments of currently preferred constructions for thefirst and second fixing means are shown in FIGS. 5 and 6. It will beappreciated that the fixing means shown in FIGS. 5 and 6 are onlyexamples of suitable fixing means that may be used in the presentinvention and that the present invention extends to include use allsuitable fixing means.

[0041] The fixing means shown in FIG. 5 is preferably the upper fixingmeans. It includes a main body portion 30 having arcuate extensions 31,32 that act to form part of openings 33, 34 through which legs 13A, 13Bcan slidably pass when the fixing means is unlocked. A clamping plate 35is attached to the main body portion 30 by a bolt 36 and nut 37. Aspring may be provided on the shank of bolt 36 to bias the clampingplate 35 away from the main body portion 30 when the fixing means is inthe unlocked position. Alternatively, and as shown in FIG. 5, springs orother biasing means 50, 51 may be provided at locations away from thebolt to bias the clamping plate away from the main-body portion 30.

[0042] The head of bolt 36 has lever 23 pivotally attached thereto suchthat lever 23 can rotate about pivot point 38. Lever 23 has an eccentric39 formed thereon which allows the lever 23 to be biased into either thelocked position or unlocked position by moving the lever 23 through adead centre.

[0043] When the fixing means shown in FIG. 5 is in the locked position,the clamping plate 35 bears against the legs 13A, 13B to thereby lockthose legs against sliding movement. When it is in the unlockedposition, the clamping plate 35 does not contact or only looselycontacts the legs 13A, 13B to thereby allow slidable movement of thelegs through holes 33, 34.

[0044] A suitable construction for the lower fixing means is shown inFIG. 6. The lower fixing means includes a main body portion 40 thatdefines holes 41, 42 for receiving the lower ends of legs 14A, 14B.Holes 41, 42 preferably have closed lower ends. Legs 14A and 14B aresuitably fixed in holes 41, 42. Hole 44, through which leg 15A of thethird leg unit can slidably move, is defined by intermediate bodyportion 43 and clamping member 45. Intermediate body portion 43 is partof main body portion 40. Main body portion 40 also includes housing 46for receiving torsion rod 25.

[0045] Bolts 47, 48 pass through main body portion 40 and extend fromclamping member 45 to housing 46. As can be seen from FIG. 6, the end oftorsion rod 25 that fits into housing 46 has an eccentric shape. Whenthe torsion rod 25 is in the position shown in FIG. 6, housing member 46is urged away from intermediate body portion 43. This in turn pullsclamping member 45 towards the main body portion 40 (and theintermediate body portion 43) by bolts 47, 48 and clamps the outer wallof leg 15A against sliding movement. In this position, the fixing meansshown in FIG. 6 is locked. If the torsion rod 25 is moved in ananti-clockwise direction by actuating lever 24 in that direction, flatland 49 of torsion rod 25 is positioned adjacent intermediate bodyportion 43 such that clamping member 45 can move away from intermediatebody portion 43. In this position, the clamping members 43, 45 do notcontact or only loosely contact leg 15A, thereby allowing slidablemovement of leg 15A through hole 44. It is preferred that clampingmember 45 is biased such that it tends to move away from intermediatebody portion 43 in the unlocked position.

[0046] From FIG. 6, it can be seen that rotation of the torsion rod 25by actuation of lever 24 can lock and unlock the second fixing means.

[0047] A side view of the apparatus of the present invention is shown inFIGS. 7 and 8. In FIG. 8, levers 23, 24 are in the locked position. FIG.7 and 8 show that torsion rod 25 is positioned laterally from the threeleg units 13, 14, 15. However, the torsion rod 25 may be positionedco-planar with the leg units if desired, or even positioned within oneof legs 14A or 14B.

[0048] Those skilled in the art will appreciate that the presentinvention may be subject to variations and modifications other thanthose specifically disclosed. It is to be understood that the presentinvention encompasses all such variations and modifications that fallwithin its spirit and scope.

1. A support means of adjustable height comprising at least one legassembly having a first leg unit, a second leg unit and a third legunit, said first and second leg units being slidably movable relative toeach other, said second and third leg units being slidably movablerelative to each other, first fixing means for selectively locking andunlocking the third leg unit relative to the second leg unit, secondfixing means for selectively locking an unlocking the third leg unitrelative to the second leg unit, first actuating means for selectivelyactuating the first fixing means between locked and unlocked positionsand second actuating means for selectively actuating the second fixingmeans between locked and unlocked positions, characterised in that thefirst and second actuating means are independently actuatable toselectively and independently lock or unlock the first fixing means andthe second fixing means, and that the first actuation means and thesecond actuating means are positioned in close proximity to each othersuch that the first actuating means and the second actuating means canbe operated essentially simultaneously by a user to thereby essentiallysimultaneously lock or unlock the first fixing means and the secondfixing means.
 2. A support means according to claim 1 wherein the firstactuating means and the second actuating means are positionedsubstantially adjacent to each other.
 3. A support means according toclaim 2 wherein the second actuating means is positioned adjacent to andbelow the first actuating means.
 4. A support means as claimed in anyone of claims 1 to 3 wherein the second actuating means is positionedaway from the second fixing means and the second actuating means isconnected to the second fixing means by a connecting member.
 5. Asupport means as claimed in claim 4 wherein the connecting membercomprises a torsion bar.
 6. A support means as claimed in any one of thepreceding claims wherein the fixing means comprises a clamping means forselectively clamping the leg units to prevent relative movement of theleg units.
 7. A support means as claimed in any one of the precedingclaims wherein the first actuating means comprises a first lever and thesecond actuating means comprises a second lever.
 8. A support means asclaimed in claim 7 wherein the first and second levers rotate aroundrespective pivot points.
 9. A support means as claimed in claim 7wherein the first and second levers include an eccentric such that thelevers can be moved to overcome a dead centre to thereby lock respectivefixing means.
 10. A support means as claimed in any one of the precedingclaims wherein the first fixing means and the second fixing means aremounted to the second leg unit.
 11. A support means as claimed in claim10 wherein the second leg unit comprises a plurality of legs spacedlaterally apart, with a first cross member extending between the legs tohold the legs in spaced apart relationship, the first cross-memberincluding receiving means for slidably receiving one or more legs of thefirst leg unit, a second cross member extending between the plurality oflegs of the second leg unit, the second cross member including receivingmeans for slidably receiving one or more legs of the third leg unit. 12.A support means as claimed in claim 11 wherein the first fixing meansclamps the one or more legs of the first leg unit and the second fixingmeans clamps the one or more legs of the third leg unit.
 13. A supportmeans as claimed in any one of claims 1 to 10 wherein the leg(s) of thefirst leg unit are telescopically slidable in the leg(s) of the secondleg unit and the leg(2) of the third leg unit are telescopicallyslidable within the leg(s) of the second leg unit.
 14. A support meansas claimed in claims 11 or 12 wherein the first fixing means is mountedon the first cross member and the second fixing means is mounted on thesecond cross member.
 15. A support means as claimed in any one of thepreceding claims comprising a tripod.
 16. A leg assembly having a firstleg unit, a second leg unit and a third leg unit, said first and secondleg units being slidably movable relative to each other, said second andthird leg units being slidably movable relative to each other, firstfixing means for selectively locking and unlocking the first leg unitrelative to the second leg unit, second fixing means for selectivelylocking and unlocking the third leg unit relative to the second legunit, first actuating means for selectively actuating the first fixingmeans between locked and unlocked positions and second actuating meansfor selectively actuating the second fixing means between locked andunlocked positions, characterised in that the first and second actuatingmeans are independently actuatable to selectively and independently lockof unlock the first fixing means and the second fixing means and thefirst actuating means and the second actuating means are positioned inclose proximity to each other such that the first actuating means andthe second actuating means can be operated essentially simultaneously bya user to thereby essentially simultaneously lock or unlock the firstfixing means and the second fixing means.